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  • 1.  Unable to interrupt SQL queries in some cases

    Posted Thu December 08, 2022 09:00 AM

    We have some problems where we are not able to interrupt queries in dbaccess with certain combinations of clients and servers. Could it be due to some traffic passing a firewall in the network? How is sqlbreak() (which I am guessing is used to implement the interrupt functionality in dbaccess) working at the tcp level? Is there some kind of OOB data being sent? 

    This is with IDS 14.10.FC7, RHEL 8.4 on server side, dbaccess 14.10.FC1, Linux RHEL 7.9 on client side.

    I suspect we only see this if the traffic passes through a firewall, because this does not affect all combinations of clients and servers.



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    Øyvind Gjerstad
    Developer/Architect
    PostNord AS
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    #Informix


  • 2.  RE: Unable to interrupt SQL queries in some cases

    IBM Champion
    Posted Thu December 08, 2022 11:54 AM
    Yes, sqlbreak + OOB.

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    Andreas Legner
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  • 3.  RE: Unable to interrupt SQL queries in some cases

    InnerCircle
    Posted Thu December 08, 2022 11:58 AM

    > How is sqlbreak() (which I am guessing is used to implement the interrupt functionality in dbaccess) working at the tcp level? Is there some kind of OOB data being sent?

    Yes, it uses "TCP Urgent Mechanism", here is a link to the (fairly old) RFC doc:

    https://datatracker.ietf.org/doc/html/rfc6093



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    Vladimir Kolobrodov
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